1. Field of the Invention
This invention relates to a non-aqueous electrolyte secondary battery, particularly relating to one with an improved electrolyte.
2. Description of the Prior Art
Various studies have been carried out relating to non-aqueous electrolyte secondary batteries with a negative electrode that is composed of lithium metal, lithium alloy or a lithium compound for meeting the requirements of high voltage and high energy density applications.
Particularly, the use of Mn0.sub.2 or TiS.sub.2 as the positive active materials for these batteries has been examined. These positive active materials show an electric potential of about 3 V as compared with Li.
LiMn.sub.2 0.sub.4 and LiCo0.sub.2 and also LiNi0.sub.2 when used as the positive active materials show an electric potential of higher than 4 V and are receiving great attention.
In other words, great efforts are being made to increase battery voltage in addition to expansion of battery capacity for the purpose of gaining a high energy density from batteries. LiCo0.sub.2, in particular, is considered as a promising positive active material since it provides the possibility of large discharge capacity and excellent charge and discharge cycle characteristics.
Furthermore, adding one or more of Mn, Cr and Fe to LiCo0.sub.2 is tried in order to improve the charge and discharge cycle characteristic that makes one of the important characteristics required of secondary batteries.